Good thread on old generation RC Lipo cycle life

[Spacey]

Read this on another forum about Lipo life cycle test:

http://www.rcuniverse.com/forum/m_3559995/tm.htm

 

[Ypedal]

from 2006 .....

 

[liveforphysics]

Read this on another forum about Lipo life cycle test:

http://www.rcuniverse.com/forum/m_3559995/tm.htm

In 2006, we were 2 generations back in RC Lipo technology.

Those packs in that thread, aside from not lasting long at all, also would explode into fireballs at the tiniest provoking, and sagged really badly compared to modern stuff.

We have come a long ways.

Also, it might be nice to change the thread to say something like, "former RC LiPo" rather than LiPo. Keep in mind, LiPo includes A123's pouches and LG's pouches etc with 10's of thousands of cycles to 90% capacity.

 

[mvly]

Wonder if pulling around 1-2C will help with cycle life. The link shows that they were drawing roughly 10C from the pack.

 

[chilledoutuk]

I am sorry some lipo's are a big improvement on what could be bought back in 2006 but not all.
I Remember back then you could easily buy kokam cells (yes the packs that didnt have balance plugs because they were so well made and matched) and enerland battery packs.

If someone offered me some some old gen kokam cells for the same price as some of these hobby king cells i would bite there arm off.

 

[El_Steak]

I have captured some real-life data with my bike's Hobby King 25C Lipo pack. (New, after 1 year - 100 cycles and after 2 years and 150 cycles). I'll continue doing so until they are not usable anymore.

Packs were not abused, always charged at 4.15V, discharged up to 3.7V (max)

I'll try and get around to graphing it in Excel.

 

[Ypedal]

I have 2 seasons on one of my bikes turnigy 20C 100v pack 5ah pack.. charged to 4.18~v ( bulk charged, cells range from 4.14 to 4.19 at end of charge ) drained to aprox 3.5ah ( 70 % DOD ) .. this will be season 3 !..

 

[ninjamik]

So..maybe some clarification on the old lipo front...just for beginners....would be handy..
In most threads the difference between lipo and Lifepo4 has been highlighted....as the difference between two chemistries I originally thought... (but I know the whole general banner for lithium polymer is Lipo so both are included)
Now the only confusing part has been that as I am now aware lipo refers to the pack type?? but are a123s not lifepo4 chemistry but in prismatic format? , but still referred to as Lipo by many members here...or is nanophosphate totally different too..I think maybe it is as they advertise as better than metal oxide!..so lifepo4 would be included in that?
so when in conversations advising Lipo as a powersource, (while highlighting the operating difficulties such as fire!) I steered well away!... do a123s also have this problem...

this is my dilemma...I really did not want to go for an unsafe un user friendly technology..that is why I went lifepo4..(I ended up buying headway 16ah cells I actually got them before joining ES) but they are massive!! so the ah I want at 72v involves a huge behemoth of a bike really...(I saw evos racebike 3. he's done a very nice job with the materials at hand but it is bloomin big!!,,,and to be honest I was warned this by other members such as snowchyld..advising investigating lipo...I did and from what I saw/read it was an older less safe but more power tech that came in pouch format...(now I understand Lipo is a format as well as a general name for lithium polymer)...it was basically the choice between lipo and Lifepo4...but where do a123s fit in?

so Lipo could be used in two totally different contexts i.e i'm sick of my SLAs, I'm going Lipo...

or don't use headway cells (lifepo4 so therefore still lithium polymer Lipo)...go LIPO....with the two different meanings of Lipo intermingled in one sentence!..so actually, dont use Lipo use LIPO..

now the term RC lipo has been thrown in too...I gathered this was like the zippy cells....I did not consider a123s as Lipo (pouch) as they come in cylindrical cells like headways and also prismatic format...

should the terms being used not be prismatic or pouch followed by the chemistry!...not just a generic multi use term..this can cause confusion...it has all become clear since doing alot of reading on this very informative forum...but it is just that a forum...so opposing views can be given...sometimes in the same post by the same person hehe

so I have ended up a little burned I think!..No worries the learning curve is just how I like it! (steep) and I was a little premature with my cash blasting after doing what I thought was enough research and opting for the safer chemistry!...oh and the one with the longest cell life...

Now again! a123s cross the two..as I am led to believe they are very safe...have large ah and c ratings but also 1000s of cycles...but what about plug and play...can the charger be mounted on the bike..or do you have to use separate multiple/chargers... I now see why so many people advocate Lipo as if a123s are in that group then the concerns usually associated with Lipo are much reduced...

basically...the headways I bought have ran me a few hundred dollars! but if a123s can meet all of these criteria then I will probably dump them (find another project for/sell) and build a whole prismatic a123 powerpack...

1. they can be charged while on the bike?... if they cant I may end up stuck with headways...this is important to everyday usage....
2. they are safer...I have gathered they can even be pierced without bad results...and I don't need an oven/fire proof box to charge in..(I thought I saw the white zombie! a123 powered just plug in to charge)
3. I dont need multiple charger setups with monitoring and such...(I was sure I have seen a cell man a123 pack with a charger like the one with my headways)

if this is correct then I will definitely go with a123s..but if it will involve not having plug and play....carrying chargers to destinations for return leg...danger of fire etc then I will find a way to cram more headways into my frame...I refuse to use back/front boxes or bags/ panniers...it is supposed to be integrated. I currently have 36v 16ah pack...I can make this hug my frame in a special shape so recon I can fit another of the same in these cells to leave room for charger etc...controller will be front/diagonal frame mounted for cooling...giving me 72v 16ah as i will series them up..evos was 20ah 72v...this seems possible without ending up with a large bike..(I am a designer so I'm sure I can be innovative) will this be enough?. 72v 16ah if I run say 30a is less than half an hours runtime...I know at top speed...but not really very far...
well at 5c...the rating of headways average i have been led to believe would be running 80a would it not...so 10-15mins ish? is this right??

I also wanted to try a switching arrangement to go 36v 32AH parallel to 72v 16AH series...well to be honest i was considering 108v but with headways I would have needed a honda gold wing or a harley for my start bike.... hehe..

sorry didn't mean to hijack this into a Q&A for me...I just posted as I am a couple of weeks into ES membership and now have a better grasp of things but total Noobs can be very confused by ambiguous terms..

I just want the best cells possible really and not waste any more money. maybe in the tech area, so no one can post on it to loose the info in pages and pages of words...the moderators or most experienced members, (justin, amberwolf, liveforphysics, bigmoose, the doc, hyena etc) sorry i dont know who you all are, could list their favourite cells and why...or an indication of what is good for what...as I still am not quite sure where a123 prismatics fit in...are they basically the best of both worlds??...are they the best cells available to the everyday man (if you can source/afford them)

 

[Ypedal]

wow ... man.... that's a lot of repeating questions that is... phew..

Loosely defined as " Lipo " is anything in a foil pouch with flat tabs that need to soldered or spot welded...

prismatic is generally a solid rectangle box with lugs or threaded assembly cells. ( they also can be spot welded with tabs... ) but this category of cell is in a hard shell case.. vs soft thin foil.

cylindrical comes in many forms, like your headways. A123 makes both 26650 ( 26mm diameter, 65mm long ) and 18650, and foil pouch, all Lifepo4 chemistry.

confused yet ?

Each chemistry has advantages and disadvantages, depending on your application and needs.

The majority of ebikes are built for 30 kms range or less, the faster you want to burn thru those 30kms means you need more capacity because it takes more energy to go faster ( wind resistance kicks in )

Yes, 16ah headway cells are HUGE, not bad on a scooter or an EV where replacing an occasional bad cell is made easy , thread off/on swap a cell..

RC lipo is what you need for light weight, high performance, when size matters, i use Turnigy packs on all my bikes.. and have built a few with Zippy packs as well.. they get charged while mounted to the bike in my kitchen while i watch TV.. in 20 minutes.

no matter what brand, size, etc etcetc... take a fully charged battery pack and short it out you will get sparks.. it's just that simple.. being reasonable and considering everything, lipo is safe to use IF you learn the do's and dont's..

My whole life i've been blowing stuff up , by accident and on purpose.. you learn to manage risk.

 

[amberwolf]

but are a123s not lifepo4 chemistry but in prismatic format?

I'm confused by your question; A123 comes in several formats, which you yourself even state a few lines later:

I did not consider a123s as Lipo (pouch) as they come in cylindrical cells like headways and also prismatic format...

Also:

a123s cross the two..as I am led to believe they are very safe...have large ah and c ratings but also 1000s of cycles

Again, A123 comes in several formats, large and small.

Anything can be charged anywhere you want, depending on how you choose to set it all up.

Safer? Depends on how you use them, the quality of the source cells, the testing done on them to weed out any potentially bad ones (either by you or by the manufacturer), etc. Even Headways could just burst out into flame if something is wrong with them or they are used beyond their ratings.

You can use single or multiple charger setups with any kind of cells. Depends on how you choose to set it all up.

There is no one "best cell", becuase it all depends on what you want out of them.

 

[ninjamik]

Sorry dude! glad you managed to de-cypher my ranting...just a little grumpy as my bikes beginnings have got a touch expensive. :wink: hehe

and cheers for the speedy reply!... so let me get this right a123 are all lifepo4..so anyone saying they're lipo is confused?

the prismatic AMP20M1HD-A do have tabs though..and look very "pouchey" soft and "foiley" so I pressume very similar to the established description of lipo! hehe

but they are deffo lifepo4?? (just kiddin' to repeat the question...

so as they have twice the energy density of headways well (2400w/kg to HDWYs 1500w/kg) so are basically half the size...I know they're different form factor.. correct so far?

I would love the power of RC lipo, pouches but this is where I refuse to budge...I want plug and play...I dont want multiple charger remove the batts 1 at a time, put in fireproof box stuff...

who has a fireproof box at all there mates houses!? I suppose 30km would do, I work in miles as I'm english and 30 miles would be way better but thats pushing 50k. I could be happy with 20 though so yea 30km would be ok...I am getting a 5403/04 of ilia when he gets his in 10-12weeks so will run at 72v or more...

I mean I'm no stranger to danger, I've got a shredded .303 shell embedded in my Lung and shoulder (my shoulder is held on with screws because of it now) and they definitely don't call me ninja for nothing its just at friends houses I tend to be "chilling out" :wink: so don't want to end up setting my mates mums curtains on fire and what Not...because trust me if It can be blow up/or sometimes if it cant..I'll find a way of blowing it up! haha...

just want the best power to weight/size ratio i can get..and still live an easy life! this means i should add the po4 and go a123 prismatic(foil with tabs)

just making sure though a123s are lifepo4 aren't they?? :wink: :wink: haha

 

[amberwolf]

Sorry dude! glad you managed to de-cypher my ranting...just a little grumpy as my bikes beginnings have got a touch expensive. :wink: hehe

Well, deep research before decision and purchase will help keep you from wasting any money. Unfortunatley it takes time to do the research, and a fair bit of reading.

There is a wiki for ES, but it is still under construction, so until people start taking data from ES threads and creating articles with it, you'll simply have to dig thru the ES threads themselves for the information.

so let me get this right a123 are all lifepo4..so anyone saying they're lipo is confused?

:? No, because LiPo simply means Lithium Polymer, which is the basic commonality to ALL flavors of Lithum-based batteries, with the possible exception of Lithium-Air (I don't know about that one). LiPo isn't exactly a cell chemistry, but rather a basic cell type.

There are types of cells that are more commonly called LiPo by more people, but they are actually usually LiCo for their actual chemistry. There's a number of threads already discussing all of that, so you should probably take a peek around for them.

I would love the power of RC lipo, pouches but this is where I refuse to budge...I want plug and play...I dont want multiple charger remove the batts 1 at a time, put in fireproof box stuff...

Again, you can build it however you want it, you can charge it however you want to. Doesn't make a whit of difference which kind of cells they are, as long as you correctly set it up for your uses and your desires when you first build it. You'll just have to research the info people have already put up about how they've done it, to find the way you want to do it.

If you want a fireproof box, build it on the bike with one.

 

[ninjamik]

yes sorry amberwolf i was a little self contradictory in my sentence about prismatic a123s...

I meant were the a123s lifepo4 like my headways but in pouch form factor...(I was mainly only looking at the 20ah pouch ones) you were not to know this obviously

also I wasn't aware anything could be charged how i wanted..thanks..I was beginning to believe you had to plug lipo cells separate into chargers and watch their charge rates etc...

I want to build my charger into the bike and just plug in to charge at my destination...with as little risk as possible.. I think I will go a123 prismatic as it is lifepo4 but way better than my headways for energy density..I don't to much care about cost..I'm not rich or anything but don't mind paying to do what I want well..I think I will try to sell the headways..theyre brand new but hey hey.. well I could run 36v 16ah but building them in would be a waste of time and materials...I could probably do with the practice building packs up though!

Haha yes sorry again I already pointed out that a123 was lipo because it was lith poly....but not lipo as in pouches (but actually does come in pouches too)

and yes I did know Lico (lithium Cobalt) was actually what people were mainly talking about! this was sort of my point...I also know there are LiNiMCo or NMC nickel manganese cobalt too..all what people call lipo...or RC lipo....

HHHmmm fire proof bike! like it!... my plan for lightweight fibreglass wouldn't help there though! I like how its a little more free like i first thought...till I caught wind of all the scaremongering..hehe....I wondered (as I'm an ex I.T engineer ) why laptop and power drill batteries (all refered to as lipo) would set on fire!! when they are used regularly by large manufacturers for everyday use items...

thanks for clearing things up...not sure if i'm gonna go LiCo (rc lipo) but i will go a123 prismatic (pouch cells) lipo but not lipo ;P haha

just gotta think of a plan for these headways! grrr....



thanks for all the great advice from both of you!

 

[amberwolf]

also I wasn't aware anything could be charged how i wanted..thanks..I was beginning to believe you had to plug lipo cells separate into chargers and watch their charge rates etc...

I want to build my charger into the bike and just plug in to charge at my destination...with as little risk as possible..

http://endless-sphere.com/forums/viewtopic.php?f=31&t=36414

I think I will try to sell the headways..

Contact Evoforce if you do; he might want some.

 

[ninjamik]

can I just throw in one more thing?? I profusely apologise for my slight thread hack...

but does either of you know if maybe I could put the headways to use as solar storage (i'm gonna charge my bike when the panels are installed)

just i still have deep cycle AGM batteries to get for that..but maybe i could build a large headway pasck so as not to waste them because size isnt so much an issue then and they would be way smaller than AGM... just not sure if they are the best kind of batts for the job as AGm are massive AH long life..although they are a large amount of cycles...if not...ebay...or the loft till i think of a project for them..

I promise to shut up now sorry!

 

[ninjamik]

and will do thanks!!

 

[liveforphysics]

Being "LiPo" has nothing to do with the chemistry, other than that it includes lithium and uses a polymer separator.

You can have LiFePO4 LiPo, like the A123 pouches you see in the Fiskar Karma sports car.
You can have NMC LiPo like you see in a Zero Motorcycle or Nissan Leaf or Chevy Volt.
You can have Lithium Titanate LiPo like you see in hybrid city buses and delivery vehicles.
You can have Lithium Spinel LiPo like you see in plug-in a plug-in Toyota Prius or Lexus.

OR

You can have Lithium Cobalt Oxide LiPo, like you see in an RC cell, which has gone through 4 distinct formula changes over time, each time the C-rate/internal resistance made big improvements, and the oxide particles got larger, decreasing surface area to evolve oxygen in an over-temp event, while the carbon black particles got smaller, and of better stacking grain sizes, along with better foil etching and bonding surfaces. Some modern RC LiPo has "stoba" type separator layers, so if the cell exceeds ~80degC, the pores simply melt closed, and the battery becomes an open circuit and the pack can't continue to heat up. Unfortunately, this separator is thicker and results in less powerful bulkier heavier cells vs not having it, but some safety conscious folks use it.


Anyways, point being, the chemistry and safety and cycle life have ABSOLUTELY NOTHING to do with being LiPo or not. You can put any battery formula, ranging from most dangerous to most safe, in a pouch (lipo) or in a prismatic shell, or in a cylindrical cell.

 

[ZOMGVTEK]

It's strange how most people think 'LiPo' or 'Lithium' says everything you need to know about a battery. Somehow, most people group ALL batteries into the same category. They assume 'Lithium' batteries are all the same, and any laptop is going to get the same cycle and calendar life. I've had issues with laptop batteries that were useless after 50 cycles, whereas I had a MacBook Air that had 700 cycles on it and reported 88% capacity. A poorly designed system is going to suck, a well designed one may work very well.

Just like Luke said, the chemistry matters quite a bit. Beyond that, a low capacity battery thats forced to run at high C rates, or to low SOC's is going to be much worse off than a larger battery driving the same system. Obviouslly there are additional concerns, but capacity and chemistry are major.

Luke, are you aware of exact cells using shutdown separators? I don't think thats a feature thats advertised, while it probably should be.

 

[ninjamik]

i know i do understand the differences in all the LIPO (li-polymer) techs...(properly now anyway. I knew what the chemistries were but not their specific characteristics) I was just pointing out the miss uses or confusions in its use to try help other newbies in future..

i have always known it referred to all lithium polymer batteries no matter what chemistry...I was just meaning what people on the forum term Lipo they mean RC lipo (LiCo) (the more dangerous one!)

well the one that always seems to come attached with an explanation...like melted pores causing heating, and if you know how to treat it it wont bite you..I understand it has it's advantages!..i'm not mocking i promise..it just always does. its the same with every user of RC lipo i have spoken to or read their posts..

just to point out how the term can be used with "double entendre" when its used in a sentence, like all lipo (lithium polymer)chemistries can be put into lipo (pouch) form factor..

thanks for all the advice! I'm just trying to make ebiking a little more accessible to future generations without confusion..

I have made a choice on a123s I think anyway!... so lifepo4 lipo batteries in lipo format..also available for RC :wink: ive downloaded the data sheets and they look pretty perfect for my build...and lifestyle :wink: hehe just have to hope my wallet wont mind too much!

at least 72v 20ah I think...i'm just going to measure up and plan the construction...

I'm very very appreciative of everyone's advice!

 

[liveforphysics]

like all lipo (lithium polymer)chemistries can be put into lipo (pouch) form factor..

ALL battery chemistry, from lead acid to NiCd to NiFe to Zebra to alkaline to carbon zinc to lithium metal (the scary sketchy non-rechargeable lithium batteries), to any type of lithium ion battery can ALL BE PUT IN A POUCH.

However, only if they use lithium ions and a polymer separator do they become LiPo. This includes a huge family of batteries, ranging from the safest in the world, to extremely sketchy (though still safer than those damn C123 etc and photo-flash non-rechargeable cells).


Calling it LiPo can mean a lithium iron phosphate ping ebike battery, or a chevy volt cell, or a hobby king nano-tech cell. The only information it provides is that it uses lithium and a polymer separator.

Don't be a part of the problem. Simply specific "RC LiPo" when you're talking about the various cobalt and spinel oxide chemistries found in various RC LiPo cells.

It's two more letters to type.

 

[amberwolf]

I was just pointing out the miss uses or confusions in its use to try help other newbies in future..

The catch is that the way you state things make them much more confusing to anyone reading your posts. You need to make sure you state things clearly and consistently, rather than repetitively with different meanings or even saying different things each time. That's how you help others for the future.

like melted pores causing heating,

No one said that melted pores cause heating. You need to go back and re-read what was said. I think that is why you are confused here and there, is because you are not fully reading what is being said.

It is extremely frustrating for anyone to explain things to help someone and have them misunderstand clearly stated things.

just to point out how the term can be used with "double entendre" when its used in a sentence, like all lipo (lithium polymer)chemistries can be put into lipo (pouch) form factor..

No one that I'm aware of refers to pouches themselves as LiPo. They might be saying they have LiPo Pouch Cells, but not that the pouches are all LiPo (which is the implication of your sentence above). They are not. Pouches are just one form of container for a cell, regardless of type, and they can be used for any chemistry. Again, you're not paying close enough attention to what you are reading.

I'm just trying to make ebiking a little more accessible to future generations without confusion..

Well, I have to say that so far you are making it HARDER for them to understand, and apparently wasting the time of the people trying to help you.

so lifepo4 lipo batteries in lipo format.

See what I mean? There is no "lipo format".

I'm very very appreciative of everyone's advice!

If you really want to show your appreciation, please pay more attention to what is actually being said.


My apologies if any of the above offends anyone, including Ninjamik, but it is too common a problem, and extremely frustrating to those trying to help.

 

[ninjamik]

I will forever when giving advice specify with clarity the meaning of my words as I know unclear advice can be conflicting....hence my attempt at highlighting the problem not being part of it!

to be fair i am quite new to the forum/specific subject (Lipo battery tech) so have found it a little difficult to concisely express my views as clearly as I usually would...hence engaging the most experienced people on the matter to increase my knowledge and understanding as rapidly as possible..

(my purposeful miss usage of it was sarcasm! :wink: ) I didn't mean to miss read anything it's very late here I'm very sleepy!...by day my powers of comprehension are exponentially increased!
I have re read and now realise you said the pores melting was a safety feature...truly sorry!...and now you have pointed that out yes that would be a good idea if the packs with this feature advertised it!..

BTW....liveforphysics (I think its luke from my reading?) that bike you made in the vid racing/beating CBRs and 650 crossers is awe inspiring! absolute kudos to you dude!...

amberwolf your a truly wise man who offers absolutely sage advice...I honestly never meant to frustrate...

 

[neptronix]

It's okay that you frustrated him. Liveforphysics is like a sea cucumber; when he gets irritated, he ejects useful information as a defense mechanism :lol: I did not know about the stoba separator layer myself, so that was interesting.

Don't feel too bad. You're pretty new here and you probably read some bad info out there on the net. This forum has a good chunk of engineer/designer/technical types who may pounce on you from time to time but see it as a learning experience. I've been there. Builds character i guess.

 

[wedge]

The chemistry of a cell refers to the materials the electrodes are made from eg. LiFePO4, LiCoO2 etc..

The form factor of a cell is the physical packaging eg. pouch, prismatic, cylindrical etc..

The electrolyte substrate of a cell is the seperator material that holds the electrolyte eg. lipo, liquid solvent etc..

The use of a polymer ("plastic") electrolyte substrates enables different form factors such as pouch cells. Lipos do not have to be pouch cells though, they can be other form factors such as the A123 18650 cylindrical cells.

The electrolyte substrate tells us the least information about the characteritics of a cell, therefore I am proposing a ban on the term "Lipo" You don't hear anybody talking about their "Lili" (lithium liquid) cells do you?

ALL battery chemistry, from lead acid to NiCd to NiFe to Zebra to alkaline to carbon zinc to lithium metal (the scary sketchy non-rechargeable lithium batteries), to any type of lithium ion battery can ALL BE PUT IN A POUCH.

I wasn't aware liquid electrolytes could be used in pouch cells? I suppose you could use some sort of rigid seperator to keep the anode and cathode apart, maybe a plastic mesh, but that would be a waste of space.

 

[Spacey]

Man I had written a long piece on my experiences with RC Lipo....mostly good....but my iPad ate them when posting grrrrr

Anyhow, can't be arsed to write it all out again but just wanted to say that I had changed the thread title and in mitigation I would add that the wife was moaning at me to come to bed.....rather than moaning whilst I'm in bed muwuhahaha.....so I started this thread in haste.

Agree 100% on using correct terminology in future.